Colloidal stabilization of beer

ABSTRACT

In the beer-making process, the wort is treated with a processing aid which is a composite of Carrageenan and polyvinyl polypyrrolidone (PVPP).

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to clarification/colloidal stabilizationof beer, and, more particularly, to upstream removal of haze-formingprecursors from beer, or prevention of haze by complexation ofhaze-producing proteins, polyphenol and other materials which arenaturally present in beer.

[0003] 2. Description of the Prior Art

[0004] Traditionally, beer has been stabilized against development ofbeer haze simply by physical storage, sometimes up to 3 months, at nearfreezing temperatures, known as “cold maturation”. During standing, muchof the least soluble materials, including the protein-polyphenolcomplexes, aggregate as particles that could be readily removed byprecipitation or filtration. However, stabilization with process aidswhich can remove the haze-forming precursors in the wort (beer beforefermentation), or beer is advantageous because it provides a beer withpredictable stability over a long period of time and simplifiessubsequent beer processing.

[0005] Accordingly, it is an object of this invention to provide a newand improved processing aid for colloidal stabilization of beer whichcan remove haze efficaciously from the wort.

[0006] A particular object herein is to provide as composite ofCarrageenan and PVPP which can remove haze advantageously by upstreamstabilization of wort in the brew house.

SUMMARY OF THE INVENTION

[0007] A Carrageenan-micronized PVPP composite is described herein whichprovides a novel and advantageous process aid for clarifying/stabilizingbeer in the brew house, which is an upstream clarification/stabilizationof beer. Suitably the materials are present in a weight ratio of 1:10 to5:10, respectively, preferably about 3.5:10, and is added to the wort asa dose rate of about 5-60 g/hl, preferably about 10-15 g/hl.

DETAILED DESCRIPTION OF THE INVENTION

[0008] Carrageenan is a refined extract of red sea weed derived fromspecies of Chondrus or Euchema sea weeds; it is a polysaccharide ofrepeating, non-homogeneous units of galactose and galactose sulfatemonomers (sulfated D-galactans).

[0009] PVPP is crosslinked polyvinyl polypyrrolidone. PVPP is insolublein beer, yet it will adsorb polyphenols from beer or wort.

[0010] The beer-making process generally includes the steps of (1)activating enzymes so that starch can be converted into sugar, which isextracted with water, (2) filtering to remove husks, and (3) boiling tocoagulate proteins and polyphenols.

[0011] In the present process, the Carrageenan-PVPP composite is addedin a single addition, together or as separate materials, about 10minutes before the end of the boil, in the kettle. The boiling action inthe kettle helps to mix the Carrageenan-PVPP composite in the boilingwort. Carrageenan is negatively charged so that there is a directelectrostatic interaction with positively charged non-microbialparticles in the wort, for example, proteins, carbohydrates and metalions.

[0012] The invention will now be described in more detail with referenceto the following examples.

EXAMPLE 1 Lab Treatment of Wort Showing Effect of PVPP, Carrageenan,PVPP/Carrageenan Composite, Towards Tannoid Content, SASPL, TotalPolyphenols and Nepholometric Titration of Haze Producing Polyphenols

[0013] A 1-liter sample of wort (all-malt) was brought to a boil and aquantity of stabilizer was added. The mixture was allowed to boil for 15minutes after addition. The volume was kept constant by addition ofdistilled water. The treated-wort was then placed in a refrigerator at0° C. and cooled for 24 hours. Visual clarity of the sample was observedand noted. An aliquot of wort was drawn from the bulk liquid andfiltered through a 1.6 μm syringe filter.

[0014] The filtered wort was analyzed for Tannoid content, SASPL(Saturated Ammonium Sulfate Precipitation Limit), Total Polyphenols andHaze Sensitive Polyphenols via the PT-Standard instrument (the abovelist of procedures are described under “Methods of Analysis”). Theresults are summarized in Table 1. TABLE 1 Effect of Process Aid DoseTannoids T-125 SASPL Total Poly- Process Aid Rate Visual (mg/l (ml/100(ml/100 phenols Ex. No. (by wt) (g/hl) Clarity* PVP K-90) ml beer) mlbeer) (mg/l) 1 Untreated 0 1 84.6 10.72 5.5 244.4 2 PVPP 10 1 57.5 11.804.8 215.7 3 Carrageenan 3.5 2 88.8 11.18 5.6 246.0 4 Carrageenan/ 13.5 357.5 12.43 4.2 220.6 PVPP (3.5:10) 5 Carrageenan/ 10.0 2 60.3 12.45 4.1231.2 PVPP (3.5:10)

[0015] From the results it can be seen that the blending of Carrageenanwith PVPP did not compromise efficacy of polyphenolic material removal(Tannins, Total Polyphenols). Visual clarity of Carrageenan/PVPP treatedsamples was equivelent or better than samples treated with Carrageenanalone.

EXAMPLE 2 Effect of Particle Size

[0016] A sample of wort was treated similarly as in Example 1 withCarrageenan/PVPP (3.5:10) blend at 15 g/hl and analyzed using the Elzonetechnique. TABLE 2 Particle Size (μm) Percentile of particles plottedagainst particle size in μm 0.1% 1.0% 6% 22% 50% 78% 94% 99% 99.9%Treated 0.206 0.207 0.219 0.258 0.361 0.571 0.862 1.187 3.333 Untreated0.205 0.206 0.222 0.278 0.424 0.739 1.184 1.962 4.331

[0017] The results show that the treated sample had smaller particles atthe indicated percentile values as compared to untreated sample. Clarityof the wort is related to the distinctly smaller particle size in thetreated sample.

EXAMPLE 3 Effect of Process Aid on Wort Clarity

[0018] A sample of wort was treated as in Example 1 with aCarrageenan/PVPP (3.5:10) composite at 15g/hl and was analyzed for haze.The total haze (0° C.) was read from cuvette using an Lg automatic hazemeter. TABLE 3 Sample Haze (EBC) Treated 7.1 Untreated 12.3

[0019] The results show that the treated sample was distinctly clearerin terms of haze.

EXAMPLE 4 Wort Yield-Plant Scale Trial

[0020] In a plant scale trial, wort was again treated withCarrageenan/PVPP (3.5:10) composite at 15 g/hl added about 10 minutesbefore end of kettle boil. The results were compared with a similarlyprepared wort without composite added and with Carrageenan alone. Themalt bill in both cases was 456 kg of malt plus 14.5 hl of water atmashing. In the test with Carrageenan alone, 3.9 g/hl of Carrageenan wasadded. The wort yield was determined by the volume of wort at kettleknock-out. TABLE 4 Sample Dose Rate Wort Yield (hl) Carrageenan/PVPP =16.0 15 g/hl Carrageenan, alone = 15.75 3.9 g/hl Untreated, no 15.5treatment used

[0021] The results show that the treated wort gave a 3.2% increase inwort yield as compared to untreated wort. When the results ofCarrageenan alone at 3.9 g/hl were compared with untreated wort, theincrease in wort yield was 1.6%.

EXAMPLE 5 Fermentation Time

[0022] The wort from Example 4 was monitored for fermentation time (dropin specific gravity against time). Samples were drawn at regularintervals to obtain data on fermentation vs. specific gravity in °Plato.The original gravity of the wort was 13.7 °Plato (at the onset offermentation) and the end gravity was 3.0 °Plato (end of primaryfermentation). The data below shows the number of hours to achieve thisresult. TABLE 5 Sample Dose Rate Fermentation Time, hrs Carrageenan/PVPP= 129 15 g/hl Carrageenan, alone = 141 3.9 g/hl Untreated, no 144treatement used

[0023] The results show that the treated sample gave a reduction infermentation time of 10.4% as compared to untreated fermenting wort.Carrageenan alone, when compared to the untreated sample gave areduction in fermentation time of 2.1%. (3 hours less).

EXAMPLE 6 Analysis of Packaged Beer From Plant Trials

[0024] Treated and untreated wort from Example 4 was put through thebeer making process and subsequently packaged. The packaged beer wasanalyzed for colloidal stability parameters. TABLE 6 T-125 Reagent TotalPT-Standard Tannoids Polyphenols P40 Reagent SASPL (ml/100 ml ofTannometer Spectrometer PT-Standard Tannometer Sample beer) (mg PVP/l)(mg/l) (ml/100 ml of beer) (ml/100 ml beer) Treated 62.16 Not Detected137.5 21.95 14.6 Untreated 11.68 39.0 168.1 27.89 14.1

[0025] The results show a marked reduction in the polyphenolic materialcontent in the treated samples as compared to the untreated samples.This is given by the analysis of Tannoid content. Total Polyphenol andT-125 Nephlometric titration for haze-producing polyphenols.

EXAMPLE 7 Beer Haze/Accelerated Aging of Packaged Beer

[0026] Packaged beer from Example 6 was subjected to accelerated agingand the total haze was monitored. TABLE 7 # of Cycles (1 cycle = 6 daysat 37° C. + 1 day at 0° C.) Permanent Haze Total Haze read at 0° C.Fresh beer at 22° C. 0 1 2 3 4 5 Sample (EBC) (EBC) (EBC) (EBC) (EBC)(EBC) (EBC) Treated 1.20 1.25 1.21 1.43 1.61 1.90 2.21 Untreated 1.511.50 1.72 1.95 2.32 2.68 3.11

[0027] The fresh-treated beer gave a lower total haze and permanenthaze. Also, the results showed that the treated sample gave much lowerdevelopment of haze with accelerated aging at 37° C.

Methods of Analysis

[0028] 1. Tannoid Content (Tannometer)

[0029] Tannoids are defined as those fractions of the polyphenoliccompounds that can be precipitated by the addition of PVP K90 to thebeer sample. They include the low and medium molecular weightpolyphenols. Haze in beer is a complex between condensed polyphenols,referred to as tannoids (T), and sensitive proteins (P) in anequilibrium governed by the law of mass action as shown in Equations (1)and (2):

P+T⇄PT  (1)

[0030] so that

[P]×[T]=k[PT]  (2)

[0031] where [P] is the concentration of polypeptides and proteins(Sensitive Proteins defined as substances giving haze when tannin isadded) and [T] is the concentration of tannoids that form precipitatewith PVP K 90 (molecular weight 350,000).

[0032] For the analysis of Tannoids, a solution of PVP K-90 is injectedinto a beer sample. The Tannoids in the beer form a precipitate with PVPK-90 through hydrogen bonding. The addition of PVP K90 is plottedagainst the formation of haze and the maxima of the peak gives theTannoid Content expressed as mg PVP/L beer.

[0033] 2. Saturated Ammonium Sulfate Titration Limit (SASPL)(Tannometer)

[0034] This test gives information on the hydrophilic character of thecolloidal constituents of beer. The addition of ammonium sulfatesolution induces haze formation in beer. The greater the value ofammonium sulfate necessary to achieve a given haze value the higher thepredicted stability of that beer.

[0035] The limit of precipitation is expressed as the volume ofsaturated ammonium sulfate solution that marks the beginning of theappearance of haze. However, there is no direct linear relationshipbetween the precipitation limit and the colloidal stability of the beer;colloidal stability is also dependent on the tannin and oxygen content.

[0036] 3. Total Polyphenols

[0037] Total polyphenols in beer is analyzed using Methods of Analysisof ASBC, method BEER-35. Both these methods read absorbance viaspectrometer and give results in ppm.

[0038] 4. Total Haze and Aging Test

[0039] The total haze is read directly from the bottle, using an Lgautomatic haze meter. The haze meter is calibrated with certified hazestandards obtained from Advanced Polymer Systems. All readings are takenwith distilled water in the measuring chamber to prevent the formationof condensation on the outside surface of cold samples.

[0040] Haze readings are taken on fresh beer samples at 22° C. and at 0°C. Aging tests are performed by incubating samples in a dry oven at 37°C. for one 6-days and then transferring to storage at 0° C. for one daybefore taking total haze readings on the cold samples. Samples are putthrough this cycle for several weeks or until an excessive value forhaze is obtained.

[0041] 5. Elzone Particle Size/Particle Count Analysis

[0042] Elzone analyzers measure a low concentration of particlesdispersed in an electrolyte solution in a sample vessel containing anelectrode. An orifice tube (a tube that has a tiny, pinhole-shapedorifice through which particles can pass) is placed inside the samplevessel. Inside of the orifice tube is a second electrode. A steadyelectric current flows from the electrode in the sample vessel to thesecond electrode inside the orifice tube. The sample solution is pulledthrough the orifice by a partial vacuum applied to the exit end of thetube. A particle blocks part of the orifice while passing through it,displacing the conductive electrolyte. This creates a change or pulse inthe otherwise steady voltage. The number of pulses reflects the numberof particles, and the size of the pulse determines the volume, andtherefore the particle size. The Elzone analyzer counts and sizes thepulses and reports comprehensive data. Particles ranging from 1200 to0.4 μm in diameter.

Summary of Benefits of Carrageenan-PVP Treatment

[0043] (a) Improved compaction of whirlpool tub resulting in an increasein wort yield. The treated wort gives more wort gallonage (volume) ascompared to untreated wort. The increase in volume of wort from the sameweight of malt used is an economic advantage in the industry.

[0044] (b) Improved wort clarity.

[0045] (c) Carrageenan-PVPP treated wort ferments better in terms of thedrop in gravity as a function of fermentation time. Shorter fermentationtimes are achieved resulting in an increase in beer production.

[0046] (d) Improved yeast vitality and crop.

[0047] (e) Improved filter run lengths.

[0048] (f) Improved beer haze, particularly reduction in totalpolyphenol and tannoid content, and an increase in predicted stabilityof packaged beer.

[0049] While a Carrageenan-PVPP composite is preferred for conveniencein the process described, it will be understood that the individualmaterials may be added separately, if desired.

[0050] While the invention has been described with particular referenceto certain embodiments thereof, it will be understood that changes andmodifications may be made which are within the skill of the art.Accordingly, it is intended to be bound only by the following claims, inwhich:

What is claimed is:
 1. In the beer-making process, the step of upstreambeer clarification/stabilizer which comprises treating the wort or beerwith Carrageenan and polyvinylpyrrolidone.
 2. A process according toclaim 1 wherein said materials are present in a weight ratio of about1:10 to 5:10.
 3. A process according to claim 1 in which said compositeis added at a dose rate of about 5-60 g/hl.
 4. A process according toclaim 3 wherein said rate is about 10-15 g/hl.
 5. A processing aid fortreating the wort of beer which is a composite of (a) Carrageenan and(b) polyvinyl polypyrrolidone (PVPP), wherein the weight ratio of(a):(b) is about 1:10 to 5:10.
 6. A processing aid according to claim 5wherein said ratio is about 3.5:10.